With Generic Scan Tool

Malfunction Indicator Lamp (MIL) in instrument cluster, checking

Meaning of exhaust MIL
The Malfunction Indicator Lamp (MIL) lights up when exhaust relevant malfunctions are recognized by the Engine Control Module (ECM).






Installation position of exhaust MIL

NOTE: The Malfunction Indicator Lamp (MIL) can blink or remain lit continuously. DTC memory must be checked in each case, diagnostic mode 3: Check DTC memory. Diagnostic Mode 3: Check DTC Memory
- Blinking: There is a malfunction that causes damage to the catalytic converter in this driving condition. In this case, vehicle must only be driven at reduced power!
- Continuously lit: There is a malfunction that causes increased emissions. Check DTC memory for Motronic control module.
- DTC memory must still be checked if there are driveablity problems or the customer has made a complaint but the MIL is not lit, because malfunctions can be stored without causing the MIL to light immediately.

Recommended special tools and equipment
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 connector test set
- Wiring diagram

Test requirement






- The respective fuses of Malfunction Indicator Lamp (MIL) -K83- must be OK:

Test sequence
- Switch on ignition:
exhaust MIL must light up.

If exhaust MIL does not light up when ignition is switched on:
- Switch ignition off.
- Check wire from ECM to exhaust MIL as follows:
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test

Vehicles with engine code AHA
- Bridge sockets 2 + 17 of test box with the respective adapter cables.

Vehicles with engine code ATQ
- Bridge sockets 2 + 47 of test box with the respective adapter cables.

Continuation for all vehicles
- Switch on ignition:
exhaust MIL must light up.

If Malfunction Indicator Lamp (MIL) does not light up:
- Switch ignition off.
- Remove instrument cluster:
- Check wire connection from Engine Control Module (ECM) to Malfunction Indicator Lamp (MIL) -K83- according to wiring diagram:
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If no malfunctions are detected in wire from Engine Control Module (ECM) to Malfunction Indicator Lamp (MIL):
- Replace Motronic Engine Control Module (ECM) -J220-.

If EPC warning lamp lights up when ignition is switched on:
- Start engine and let run at idle:
Exhaust MIL must go out after a few seconds.

If Malfunction Indicator Lamp (MIL) does not go out:
- Switch ignition off.
- Remove instrument cluster:
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test

Vehicles with engine code AHA
- Check wire connection between test box socket 17 and instrument cluster for short circuit to Ground (GND) according to wiring diagram:

Vehicles with engine code ATQ
- Check wire connection between test box socket 47 and instrument cluster for short circuit to Ground (GND) according to wiring diagram:

Continuation for all vehicles
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If no malfunctions are detected in wire from Engine Control Module (ECM) to Malfunction Indicator Lamp (MIL):
- Replace Motronic Engine Control Module (ECM) -J220-.